в файле zigbee-shepherd-converters/devices.js добавляем в список devices описание нашего устройства:
    {
        zigbeeModel: ['JAGER_KEYPAD20'],
        model: 'JAGER_KEYPAD20',
        vendor: 'Custom devices (DiY)',
        description: '',
        supports: '',
        fromZigbee: [fz.keypad20states],
        ep: (device) => {
            return {'btn_1': 1, 'btn_2': 2, 'btn_3': 3, 'btn_4': 4};
        },
    },


в файле zigbee-shepherd-converters/converters/fromZigbee.js добавляем конвертеры:
    keypad20states: {
        cid: 'genOnOff',
        type: 'attReport',
        convert: (model, msg, publish, options) => {
            const ep = msg.endpoints[0];
            const button = getKey(model.ep(ep.device), ep.epId);
            const state = msg.data.data['onOff'] === 1 ? true : false;
            if (button) {
                return {[button]: state};
            }
        },
    },


в iobroker.zigbee/lib/devstates.js надо добавить состояния и описание устройства:

const states = {
...
    keypad_btn1: {
        id: 'btn_1',
        prop: 'btn_1',
        name: 'Button 1 click event',
        icon: undefined,
        role: 'state',
        write: false,
        read: true,
        type: 'boolean',
    },
    keypad_btn2: {
        id: 'btn_2',
        prop: 'btn_2',
        name: 'Button 2 click event',
        icon: undefined,
        role: 'state',
        write: false,
        read: true,
        type: 'boolean',
    },
};



const devices = [
...
    {
        vendor: 'Custom devices (DiY)',
        models: ['JAGER_KEYPAD20'],
        icon: 'img/diy.png',
        states: [states.keypad_btn1, states.keypad_btn2],
    },
];